Longest Common Prefix using Python

Longest Common Prefix is one of the popular problems in Leetcode. It is asked in coding interviews by companies like FAANG many times. Here you need to return the longest common prefix among all the strings in an array of strings. So, if you want to learn how to solve the Longest Common Prefix problem, this article is for you. In this article, I will take you through how to solve the Longest Common Prefix problem using Python.

Longest Common Prefix using Python

To solve the Longest Common Prefix problem, you need to find the most common prefix in all the strings of an array. For example, you are given an array of strings [“flower”, “flow”, “flight”], in this array, the most common prefix among the first two items is “flo”, so, if the third element would have been “flowing”, then the longest common prefix would have been “flo”. But as the common prefix among all the strings of the array is “fl”, the output should return “fl”.

I hope you now have understood what the longest common prefix means. Now here’s how to solve this problem using the Python programming language:

strs = ["flower", "flow", "flight"]

def longestCommonPrefix(strs):
    l = len(strs[0])
    for i in range(1, len(strs)):
        length = min(l, len(strs[i]))
        while length > 0 and strs[0][0:length] != strs[i][0:length]:
            length = length - 1
            if length == 0:
                return 0
    return strs[0][0:length]

print(longestCommonPrefix(strs))
Output: fl

So this is how you can solve this problem using Python. You can find many more practice questions to improve your problem-solving skills using Python here.

Summary

To solve the Longest Common Prefix problem, you need to find the most common prefix in all the strings of an array. For example, in an array of strings [“flower”, “flow”, “flight”], the most common prefix is “fl”. I hope you liked this article on finding the longest common prefix using Python. Feel free to ask valuable questions in the comments section below.

Aman Kharwal
Aman Kharwal

Coder with the ♥️ of a Writer || Data Scientist | Solopreneur | Founder

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